Underfired regenerator coke oven



c. oT-ro 2,224,920

UNDERFIRED REGENERATOR COKE OVEN Filed July l, 1958 3 Sheets-Sheet l//////Q /n/Q/ 13 CARL OTTO Dec. 17, 1940. c. oTTO UNDERFIRED REGENERATORCOKE OVEN Filed July 1, 1938 3 Sheets-Sheet 3 -ATTO R N EY and adaptedto be heated by the combustion in Y Patented Dec. 17, 1940 UNITED STATESUNDERFIRED REGENERATOR COKE OVEN Carl Otto, The Hague, Netherlands,assignor to Fuel Refining Corporation, Dover, Del., a corporation ofDelaware Application July 1, 1938, Serial No. 216,862

8 Claims.

The general object of the present invention is to provide improvedheating means in an underred regenerative coke oven battery, andparticularly in a battery having vertical heating ues said iiues ofeither a lean-fuel gas which is, or a rich fuel gas which is not,regeneratively preheated. More specifically, the object of the inventionis to provide such a coke oven battery with improved means forregulating the relative amounts of heat imparted to the coking chambercharges at different levels.

In accordance with the present invention, I make use of so-called highand low burners, i. e., richfuel gas supply passage outlets opening tothe combustion ues at different levels. The underfired, regenerative,hairpin flue, coke oven batteries now in Wide use, are customarilyprovided with high burners in some flues and low burners in other ues.In accordance with the present invention, a low burner and a high"burner is provided in each of a plurality of flues not necessarily ofthe hairpin type, which are distributed along the length of each heatingWall, and the invention is characterized by the disposition of thenumerous gas supply passages which extend up to the burners from thebottom of the masonry mass of the battery, and are regulable.

to permit the amounts of gas simultaneously adjusted, to increase theheat supplied to the upper, or to the lower portion of the charge,Without necessarily changing the total amount of gas burned in each twinflue, and passing therefrom into the associated regenerators.

In accordance with the present invention, I'

avoid difliculties which would be experienced if all of the numerousuprising passages for the different burners in a single heating wallextended upwardly through the subjacent pillar wall, by locating some ofthe. supply passages for burners in one heating wall in each of two, orin some cases, three different regenerator division Walls. In preferredconstructions, the supply passages for some, at least, of thesimultaneously operable burners in two adjacent heating walls extendupward through a regenerator division Wall intermediate the pillar wallsbeneath the two heating walls. In the preferred forms of the invention,also, I supply gas tothe uprising supply passages through horizontaldistribution conduits extending transversely of the battery, within thelower portion of the masonry mass or body of the under-l red battery, inthe special manner disclosed and generically claimed in my co-pendingapplication illed June 6, 1938, Serial No. 212,084.

The various features of novelty which characterize the present inventionare pointed out underflred coke oven battery, the section being Fig. 2is a partial vertical section taken on the 15 line 2-2 of Fig. 1;

Fig. 3 is a vertical section, on an enlarged scale, of a device shown inFig. 2;

Fig. 4 is a vertical section, on an enlarged scale, of another deviceshown in Fig. 2;

Fig. 5 is a partial section on a larger scale than that of Figs. l and2, with its right hand portion taken on the line i-I, and its left handportion taken on the line 5-5 of Fig. 2;

Fig. 6 is a view taken similarly to Fig. 5 illus- 25 trating amodication of the construction shown in Figs. 1 5;

Fig. 7 is a sectional view taken similarly to Fig. 5 illustrating amodiied construction;

Fig. 8 is a partial horizontal section taken on 30 tion being 'taken onthe line 9 9, and theleft l hand portion on the line 9-9A of Fig. 10;

Fig. 10 is a section taken atright angles to Fig. 9 with its left,central and right hand portions taken on the lines I0-I0, Ill-IDA, andlB-IUB, respectively, of Fig. 9; and

Fig. 11 is a partial section on the line Il-ll 40 of Fig. 7.

In Figs. 1-5 of the drawings, I have illustrated theuse of one form ofthe present invention in a regenerative underfired, horizontalcoke ovenbattery comprising a brickwork block or mass sup- 45 ported on a deckmember` A, through an interposed masonry layer AA. The vdeck member A iscustomarily in the form of a slab oi reinforced concrete, and as shown,is divided into sections,

by expansion joints A', the said joints extending 50 upper storyincludes horizontally elongated coking chambers C, alternating withheating walls D.

' Each of the latter is formed with vertical ilues d alternating withvertical iiues d'. The ilues d and d are connected at their upper endsin pairs to form twin or hairpin flues. Each twin or hairpin fluecomprises two side by side branches, d and d', connected at or adjacenttheir lower ends, as hereinafter explained, to different regenerators,and to different rich fuel gas supply passages, the latter having 1ow"and high burner outlets D and U, respectively. 'I'he lower storycomprises two side by side regenerator chambers E and e, between eachtwo adjacent pillar walls F, there being one pillar wall F directlybeneath each heating wall D. Midway between each two adjacent pillarwalls F, and interposed between the corresponding regenerators E and e,is an intermediate regenerator division wall f.

The regenerators E and 'e have sole channels E' and e through whichwaste heating gases pass from the regenerators through correspondingreversing valves G, to a waste heat tunnel G at one side ci' thebattery, or, alternatively and as shown in Fig. 1, there may be a wasteheat tunnel G at each side of the battery, with each end of each solechannel E and e connected through a corresponding valve G to each tunnelG'. With a tunnel G' at each side of the battery, each of theregenerators E and e, and each of their sole channels E and e', may bedivided into two aligned sections, by a vertical partition E extendinglongitudinally of the battery adjacent its central plane.

The coke oven battery shown in Figs. 1 to 5, is a so-called combinationoven battery, adapt# ed for operation either with a rich fuel gas whichis not regeneratively preheated, or with a`lean fuel gas which needs tobe regeneratively preheated. In operation with rich fuel gas, all of theregenerators E and e are used in preheating combustion air. Inoperation, with lean fuel gas,

the regenerators E are used in preheating combustion air as in rich gasoperation, but the regenerators e are used in preheating the lean fuelgas. l

Each of the regenerators E and e, alternately receives products ofcombustion from,`and supplies preheated air 'or lean fuel gas to one setof twin flue branches d or d in each of the two heating walls above thepillar walls F at the opposite sides of the regenerators. In thearrangement shown, fuel gas is supplied at any one time to the uebranches d, in every second heating wall, and to the branches d in theremaining heating walls.

All of the forms of the invention illustrated herein are alike in havingregenerator and heating flue connections H, H', h and h', of thecharacter shown best in Figs. 9 and 10. Each regenerator E is connectedby an inclined duct or passage H to one branch, d or d', of each hairpinuevin the heating'wall D above the pillar wall F at the right of saidregenerator, and is connected by an inclined duct or passage H', to eachcorresponding hairpin flue branch d' or d, respectively, in the heatingwall D above the pillar wall F at the left of the'regenerator.- Eachregenerator e is connected by oppositely inclined ducts or passages hand h to the same hairpin ue branches d or d' to which the regenerator Eat the opposite side of the adjacent intermediate division wall f, areconnected by its ducts H and H'. With the particular arrangementdescribed,

two regenerators are both on regenerators, the

vregenerator E of the pair then preheating upflowing air, and theregenerator e preheating upflowing air or lean gas, accordingly asv richor lean gas fuel is used in heating the battery. In the case of each tworegenerators E or e, at the opposite sides of a pillar wall F, however,one` is necessarily an off regenerator during the periods in which theother is an 0n regenerator.

In the form'of the present invention shown in Figs. 1 5, the uprisingpassages through which rich fuel gas is supplied to the heating wallilues, are not formed in the `pillar walls F, as has been customaryheretofore, but in the intermediate division walls f, as they are in myabove mentioned prior application. Thus as shown in Figs. l and 2, richfuel gas is supplied to the twin flue brances d in each heating wallthrough a set of channels I formed in the adjacent intermediate divisionwall f at the right of the heating wall. The chanels I in each wall falternate with channels I supplying rich fuel gas to the twin fluebranches d in the heating wall immediately to the left of said wall f,the upper ends of the channels I and I' being bent to the left andright, respectively, as is shown clearly in Fig. 2.

Since the two regenerators at opposite sides of each intermediatedivision wall f are both on, or both ot regenerators at any one time,and are both on regenerators when rich fuel gas is being suppliedthrough the channels I and I in said wall, there is no pressuredifferential tending to create any signicant leakage from eitherregenerator into the other, and small tendency to leakage into eitherregenerator from the rich fuel gas supply channels I or I' in said wall,even though cracks form, or joints open in said wall.

A leakage barrier in the form of a metal plate or web J is incorporatedin each oi the walls F. The plate or web J is preferably formed of arefractory, corrosion resisting metal such as a nickel-chromium alloy,adapted to safely with-- stand the maximum temperatures to which it issubjected and as shown, each plate or web J is centrally disposed in thewall F, in which it is incorporated, and extends from below the bottomlevel of the sole channels to a level somewhat below the level of thetops of the regenerators, so that the plate is not subjected to therelative high temperatures prevailing in the top portion of the well F,where the risk of objectionable leakage is relatively slight, becauseo1' the relatively small difference between the pressures at theopposite sides of the wall.

The ducts or passages I and I in each of 'the walls f may receive richfuel gas from a distribution pipe Alocated in the basement space a ashas n been heretofore customary. Advantageously, however, rich fuel gasis supplied to the passages I'and If in each wall f from a horizontaldistribution channel K located in the special masonry layer AA, which isinterposed between the or wire o3 or suitable size mmugn the bore or theorifice member vAs shown in Fig. 3, the

deck A and the coke oven brickwork mass to receive the channels K,- andthe horizontal distributionchannel KAand KB, through which lean Vgas andair are supplied to the regenerators E and e,

to b e preheated therein. As shown, each of the air to be preheated inthe oven regenerator E is supplied by a main M running longitudinally ofthe battery, preferably at a pressure slightly abov atmosphericpressure. The mmn M is advantageously located at the opposite side ofthe battery from the rich gas mainv L, and is connected to thecorresponding end of each pipe KB through a reversing valve M'. Inoperation with rich fuel gas, each pipe K may receive decarbonizing airthrough a corresponding reversing valve M3 and eutoi valveM4, from themain M, during the periods in which it ih not receiving rich gas fromthe main L. Each distribution pipe lKA is connected by a reversing valveM' to a supply main MA extending longitudinally of the battery, adjacentone orthe other of the mains LA and M. The main MA serves to supply leanfuel gas to the regenerators e, when the battery 'n axial au ent withthe pipe and formed in is being heated by combustion of lean fuel gas,

and to supply air to the regenerators e under the same pressure as itissupplied by the main M during operation with rich fuel gas.

The amount of gas supplied to each channel I and I', caribe regulatedfrom the basement space a. To that end, each pipe K is provided with aseparate outlet for each passage' Igand I served by the pipe, each suchoutlet comprising concentric pipes 0 and OA, as shown in Fig. 3. Eachpipe O is vertically disposed and has its axis external to thecorresponding pipe K, but separated from the periphery of the latter bya distance less than the internal radius of the pipe O. Each pipe O isformed with a. port in its `side in register with a correspending portin the wall of the pipe K. Advantageously, each pipe O is welded to thecorresponding pipe K at the margins of their respective registeringports. of each pipe OA is appreciably less than the in side diameter ofthe corresponding pipe O, so that the lower end oi' the pipe 0A is incommunication with the pipe K through the annular space Vbetween thepipes O and OA. The pipe 0 has its upper end inbent into contact with,and welded to the pipe O, which extends upward into the lower end-of thecorresponding channel I o r I.

'I'he lower end of the pipe 0A extends down to or below the top of thebasement space A, and is accessible from that space on the removal oithe cap O whichnormally is threaded on land closes the lower end of thecorresponding pipe' O. As shown, the amount ciegas supplied throughieach outlet connection from the pipe K, may be regulated, by variablythrottling the corresponding pipe OA.. As shown, each pipe OA isthrottled by an oriilce member O2 removably seated in the lower end o!the pipe OA. By replacing oneoriiicemember` O2 by another of slightlylarger or smaller bore, the pipe OA may be variably throttled.Additional regulation may be had by extending an obturator rod Theoutside diameter.

obturator O3 rests upon a removable plug closing an opening in the endof the cap member O'.

By removing the -plug O4, the obturator 03v is made removable forcleaning or for replacement by an obturator of diierent diameter, andthe bore of the orifice member O2 ymay be readily cleaned. As shown, atubular wire mesh screen Os having its upper end closed, is mounted on areduced upper end portion of the orifice member 02. The screen O5eliminates risk of the small backre explosions which may otherwise occurin the pipe K under certain conditions, and also tends to preventobjectionable dirt deposits on the orifice wall ofthe member 02.

In the preferred construction illustrated, each of the horizontaldistribution pipes KA and KB is provided with outlets distributed alongits .length and-corresponding in number and location to the ues in aheating wall, and each such outlet may have its flow capacity regulatedfrom the basement space, a. As shown, each outlet from the pipes KA andKB comprises a vertical` pipe P connected -t'o and in communication withi* the corresponding pipe KA or KB, as each pipe O is connected to andin communication with a pipe K. Thev lower end of each pipe P extendsinto the basement space and is normally closed' by a removable cap P'.The upper `end'of each pipe P extends into a masonry channel F', in.

the -lower portion oi' the pillar wall F alongside the correspo solechannel E' or e. As

shown, the flow capacity of each outlet pipe P.

is dependent on the diameter of an. obturator P2, shown as of ovoid formand axially disposed in the pipe above the ports through which itlcommunicates with the corresponding pipe KA or m. The obturator P2 isreplaceably mounted on theupper end of a rod P3 which has its lower endresting on the corresponding cap P'. As shown, the rod P3 is providedwith spider arms P4 adjacent its upper end through which the rod iscentered in the pipe P.

As shown, each port F' terminates at its upper end in a horizontal por-tIli opening into the lower portion of the corresponding regenerator E ore. Each port F2 is elongated in the direction of the regenerator intowhich it opens, and, as shown, is in register with a port formed in theside ange of Athe adjacent tray-like parts E2 supported on brlckworkshoulders formed with side walls of'the regenerator. The ported trays E2serve as supports for the checkerbricksiii3 in the regenerator. In thepreferred construction, the checkerbricks are shaped to form regeneratorpartition walls E4, extending vertically from the top to the bottom ofthe regenerator and dividing the latter into compartments, eachreceiving air or lean fuel gas to be preheated at its lower end througha corresponding outlet pipe P and passage F', and communieating at itsupper end through one duct H and one duct H' or one duct hand one ducth' with one twin flue branch in each of two adjacent regenerators atthejunction at thebottom of each regenerator with its sole channel. Theports in the plates E5, which may be formed of D2 in the flue branches dof each heating wallf is at the upper end of a corresponding rich gassupply channel I extending upwardly in the regenerator division 'wall'fat the right of the heating wall. The channels I' in the sameregenerator division wall ,f lead to the low and high burner outlets D'and Da in theA twin flue branches d' in the heating wall at the right ofthe wall f. With the described arrangement,

as will be apparent to those skilled in the art.

at any one time combustion will be initiated in the flue branches d ofheating walls alternating with heating walls in which combustion isbeing initiated in flue branches d'.

As will be understood, the reversing valves L' are normally adjusted sothat distribution pipes K which at any instant are receiving rich fuelgas fromthe main L. alternate with pipes K then out of communicationwith that main. In consequence, at any one time, in normal rich fuel gasoperation, the walls f containing channels I and I' through which gas ispassing, alternate with walls f containing channels I and I',throughwhich rich fuel gas isnot passing, but into which decarbonzing air maythen be passing. By a'suitable throttling adjustment of thecorresponding outlet OA, the amount of gas burning 40 at a low burner D'may be increased, and the heat supplied to the bottom ofthe charge maybe correspondingly increased. Similarly, by a throttling adjustment ofthe corresponding outlet pipe OA, the fuel gas issuing from each highburner outlet D2, may be increased, and the amount of heat imparted tothe to'p of the charge may therebybe increased. By suitable relativethrottling adjustments of the two outlet -pipes OA through which gas issupplied to the low andv ESQ high burners D and D2 in the same fluebranch, d

or d', the relative :amounts of gas discharged by the two outlets may be.varied without changing the total amount of fuel gas supplied to the uecontaining the two outlets, and therefore without disturbing thepreheating action or capacity of the corresponding regenerator.

Advantageously, and as shown, the outlets D are located at a'greaterdistance above the bottoms of the ues and coking chambers than it hasbeen customary heretofore to locate the high burners in coke ovenheating walls having high and low burners. This increase in height ofthe high burner outlets, facilitates, and contributes to, the desiredregulation of the top and bottom heating actions, and with the accurateand easily effected adjustment of the gas supplies to the differentburner outlets provided for, the unusually high level of the outlets D2involves no objectionable risk of overheating the topof the at one end,andthe branch d' at the opposite endl outletin each of its flue branchesd'.

struction shown in Fig. 6, and the construction shown -in Figs. 9 and10. ,As shown in Fig. 9, high burner outlets D2 are4 provided only inthe flue branches d, which have low burner outlets D adjacent theirbottoms.V 'I'he ue branches 5 d', other than the one at theend yof theheating wall, are provided with burner outlets D3, at a level somewhatabove the level of the outlets D', but appreciablj'r below the level ofthe outlets D2.

Fig. 6 illustrates the arrangement of the channels I and IA in the wall,f of a battery .in which rich fuel gas is supplied wholly throughpassages 4I and I' in the walls f, to heating walls, each like thatshown in Fig. 9, in having but one burner l5 In lieu of forming thesupply passages for the set of high burner outlets, and for the set oflow burner outlets of a heating wall, in the two adjacent intermediatewalls f, it is sometimes advantageous to form the supply passages forone 20 set of burner outlets' in said intermediate walls, and to formthe supply passages for the other set of burner outlets in the pillarwall F directly beneath the heating wall. In such cas, the supplypassages running to the different sets of burners in a single heatingwall will receive gas from different distribution pipes, Aand by varyingthe relativev gas pressures in those pipes, the charge heating effect ofthe top of each heating wall can be increased or decreased relative tothat of the bottom of the wall. Figs. 9 and 10 illustrate onearrangement, and Figs. 7, v8, and 1l another arrangement in which oneset of burners in each heating wall are supplied with gas throughpassages extending vupward through the subjacent pillar wall.

In the battery construction. illustrated in Figs. 9 and 10,richfuel gasis supplied to the high burner outlets D2 in each heating wall, throughvertical passages I2 formed in the pillar Wall F directly beneath theheating wall, and gas is supplied to the low burner outlets D' and D3 ofeach heating wall, through passages I and I' located as are thepassages'I and I supplying rich fuel gas to the burner outlets D' of theconstructions shown in Figs. 1-5.

The passages I2 in each wall F, receive rich fuel gas through acorresponding distribution channel KC, which is located in the masonrylayer.AA, andv which may be exactly like the previously describedchannels K in respect to its connection to the supply 'main L, and inthe arrangement of itsregulable outlet pipes O and OA. Advantageouslyand as shown, however, each pipe KC is somewhat smaller in diameter thanthe pipes K, since the amount of gas supplied by each pipe KC issubstantially smaller than that supplied' by each pipe K. The reductionin diameter of the pipe KC is particularly desirable in the arrangementshown in Fig. l0, in which the pipe KC is necessarily quite close to anadjacent distribution pipe KA or KB. With rich fuel gas supplied to thehigh burneroutlets Dz in veach heating wall through passages P from adistribution pipe KC supplying gas only to those channels and burner 35outlets, the amount of gas supplied to those high burners D2 may bevaried by varying the gas pressure in the distribution pipe. Thatpressure may be varied by variably throttling the supply connectionleading from the main tothe pipe KC.

Figs. 7, 8 and 1l illustrate an arrangement of rich fuel gas supplychannels I2 and I3, extending upwardthrough a pillar wall F, adapted tovsupply fuel gas to the high burner outlets of a heatl ing wall abovethe pillar wall and like the heating n wall shown in Fig. 1, in having alow burner outlet D in every ue d and d', and in having a high burneroutlet D2 in every flue except the two end nues of the wall. As shown inFigs. 7 and 8, the channels I2 are adapted for connection to the burneroutlets D? of the fiues d of the heating wall shown in Fig. 1, andchannels I3 which alternate with the channels I, are adapted forconnection to the high burner outlets D2 in the ues d'.

As shown in Fig.4 11, there are two horizontal rich gas distributionpipes KC and KD at the opposite sides of the row of pipes OA associatedwith the different vertical channels I2 and I3 of a single heating Wall.The horizontal distribution pipe KC, as shown, is in communication onlywith the pipes OA associated with the channels I2, and the distributionpipe KD is in communication only with the pipes OA connected to thechannels I3. When combustion isbeing initiated in the flues d, thedistribution pipe KC will be in, and the dis-v tribution pipe KD will beout of communication with the gas supply main, but the pipe KD will thenordinarily be connected to a source of decarbonizing air. When the flowthrough the ilues and regenerators is reversed, the pipe KD is connectedto the gas supply main, and the pipe KC is disconnected from the gassupply main and connected to the source of decarbonizing air.

The possibility of leakage from the rich gas supply channels I and I',I2 or I3, to the regenerators at the sides of the regenerator wallincluding the channels, may be eliminated or substantially minimized bythe use of metallic barrier means incorporated in said wall. In general,the risk of leakage from the channels in the intermediate regeneratordivision walls f, is not serious enough to justify the incorporation ofmetallic barriers in those walls, but with the considerable diierencebetween the pressures at the `opposite sides of each wall F, the simplemetal plate barrier J, of the construction first described, mayadvantageously be replaced by barrier means which encircle the tubulartile forming the walls for rich gas channels formed in said wall. Such abarrier JB is illustrated in Figs. 8 and ll. The barrier JA may beformed of metal plate material like that used in the previouslymentioned barrier J, and may extend from the bottom of the coke ovenbrickwork about as high as do the barriers J. As shown in Fig. 8, 'eachbarrier JA is formed of metal sections, each extending between a passageI2 and an adjacent passage I3, and each having its vertical edges bentto form half cylinders JA' and JA. The adjacent half cylinders JA' andJA2 of the two sections at opposite sides of each supply channel I2 orI3, encircle the tiles I forming the wall oi said channel in the mannerin which the walls of rich gas channels are customarily formed.

Hairpin ue coke ovens with a single burner in each lbranch of eachhairpin flue and with some of the burners distributed along the heatingwall and located at a different level from that of other burnersdistributed 'along the heating wall, are now in extensive and such use.In many cases, such a "high and low burner arrangement permits of allrequired regulation of the relative charge heating effects of the upperand lower portions of the beating wall. In some cases, however,particularly wlth large capacity ovens having relatively high heatingwalls, the required regulation of top and bottom heating effects cannotbe 'obtained with sucha high or low burner arrangement without anundesirably large difference in the amounts of rich fuel gassimultaneously supplied to adjacent flues. The maintenance of emcientcombustion and regeneration conditions, require that the fuel gas andcombustion air should be supplied to the different fines insubstantially the same proportions, and require that the relativeamounts of preheated combustion air and fuel passing to adjacent iiues,and the r'elative amounts of products of combustion simultaneouslypassing from said ues to a regenerator should not vary greatly.

With simultaneously operable high and low burners in the same verticalues as hereinbefore described, it is possible to relatively proportionthe top and bottom heating eiects of a heating Wall through as Wide arange as is practically desirable without significant change in theamounts of rich fuel gas and preheated combustion air supplied to eachhairpin flue, and consequently without significant variation in theamount of products of combustion passing from the hairpin flue to theregenerator associated therewith.

My prior Patent No. 1,770,285, granted July 8, 1930, discloses anunderred coke oven with hairpin heating flues, and with a high burnerand a low burner in each branch of each hairpin flue, and with thesupply passages for all the rich gas burners in each heating wall,extending up from the basement space of the battery through the pillarwall directly beneath the heating wall. The multiplicity of supplypassages in each pillar wall in the construction shown in said patenthas a tendency to weaken and increase the risk of leakage through thepillar Walls which may be wholly or largely avoided by the use of thepresent invention.

While in accordance with the provisions of the statutes, I haveillustrated and described the best forms of embodiment of my inventionnow known to me, it will be apparent to those skilled in the art thatchanges may be made in the form of the apparatus 'disclosed withoutdeparting from the spirit of my invention as set forth in the appendedclaims and that in some cases certain features of lmy invention may beused to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new anddesiretosecure by Letters Patent is:

1. In an underred regenerative coke oven battery comprising a masonrymass including coking chambers and heating walls alongside the cokingchambers in an upper portion, and'vregenerators and regenerator divisionwalls in a lower portion, of said mass, all extending transversely ofthe battery, said heating Walls having vertical liues connected at theirupper ends in groups for simultaneous upfiow in one or more, and downlowin one or more other fiues, of each group, the improvement comprising alow burner and a high burner in each of a plurality of flues in eachheating wall in which the gas flow at any one time is in the samedirection and at least one burner. in the other flues of the heatingwall, and means for supplying gas to the said burners in each heatingwall comprising separate supply passages for the different burnersextending up from, the bottom of the mass, some through one and othersthrough another of two different regenerator division walls.

2. In an underred regenerative coke oven battery comprising a masonrymass including coking chambers and heating walls alongside the cokingchambers in an upper portion, and regenerators and regenerator .divisionwalls in a lower ends in pairs with each flue of the pair forming onebranch of a hairpin iiue, the improvement comprising a low burner and ahigh burner in one,

branch, and at least one burner in the other branch of each of aplurality of hairpin ues in each heating Wall, and means for supplyinggas to said burners comprising separate supply passages for the diierentburners extending up from the bottom of the mass through regeneratordivision walls, the supply passages for some of the burners in twoadjacent heating walls extending up through the same division wall.

3. In an underiired regenerative coke oven battery comprising a masonrymass including coking chambers and heating walls alongside the coklngchambers in an upper portion, and regenerators and regenerator divisionwalls in a lower portion of said. mass, all extending transversely ofthe battery, and each of said heating walls having vertical fiuesconnected at their upper ends in pairs with each flue of the pairforming one branch of a hairpin flue, the improvement comprising a lowburner and a high burner in one branch, and at least one burner 'in theother branch of each of a plurality of hairpin ilues in each heatingwall, and means for supplying gas to said burners comprising separatesupply passages for the diierent burners extending up from the bottom ofthe mass through regenerator division walls, and distribution conduitsextending transversely of the battery and each supplying gas to a numberof' said passages, the supply passages for some of the burners in eachheatingwall, extending up some through one and low burner and a highburner in one branch, and

at least one burner in the other branch, oi each i of a plurality ofhairpin nues in each heating walL separate gas supply passages for thesaid High burners in each heating wall extending upward from the bottomof the' mass through one regenerator division wall adjacent the lastmentioned heating wall and separate gas `supply passages for the saidlow burners in the same heatng wall extending up from the bottom of themass through a second regenerator division wall adjacent the last'mentioned heating wall.

5. In an underiired'regenerative coke oven bat-V tery comprising amasonry mass including coking chambers and heating walls alongsidethe'coking chambers in an upper portion, and regenerators andregenerator division walls in. alower portion of said mass all extendingtransversely to the battery and each of said heating walls havingvertical nues connected at their upper ends in pairs with each ilue oi apair forming one branch of a hairpin nue, the improvement comprising alow burner and a high burner in one branch,`and at least one burner inthe other branch, of Aeach of a plurality of hairpin ilues in eachheating wall, and separate gas supply passages 'for-each of the saidhigh and low burners in one heating wall, and for each of the burners inthe said other flue branches in an adjacent heating wall, extendingupward from the bottom of said mass through anadjacent regeneratordivison wall.

6. In an underiired regenerative coke oven battery comprising a'masonrymass including coking chambers and heating walls alongsidethe coking vchambers in an 4upper portion, and regenerators and regenerator divisionwalls in a lower portion, of said mass, all extending transversely ofthe battery, and each of said heating walls having vertical nuesconnected at their upper ends -in pairs with each ilue ofa pairiormingone branch of a hairpin flue, the improvement com-A prising a setof high burners, a set of low burners and a third set of burners foreach heating wall, each of a plurality of said hairpin ues in said.heating wall includingone high burner and one a burner of the third setin its other branch and separate gas supply passages for the diilerentburners extending upirom; the bottom oi said mass to the burners throughregenerator division walls, the supply passages for each set of burnersin each heating wall extending up through a regenerator division wall,dierent from those through which the supply passages for the other setsof 'burners' extend, the supply passageszfor another set of burnersextending up through a regenerator division wall at one side, andsthesupply passages ior the third set of burners extendand regeneratordivision walls in a lower por,

tion, oi said mass, all extending transversely of the battery, and eachof said heating walls having vertical nues connected at their upper endsin pairs with each ue of a pair forming one .branch of a hairpin nue,the improvement comprising two alternately operable sets `of highburners, and two alternately sets of low burners for each heat'- ingwall, each of a plurality of said hairpin ues including one of said highburners and one of said low burners in each o i'rits branches andseparate gas supply passages extending up from the bottom of the masstothe-burners through regenerator division walls, the supply passages fortwo sets oi' burners ineach heating wall exte'nding up .through oneadjacent regenerator division wall, the supply passages for a third setof burners yin said heating wall extending up through a regeneratordivision wall at one side,

vand the supply passages for the fourth set of burners in said heatingwall extending up through the regenerator division wall at the oppositesides of the first mentioned division wall, the high and low burners ineach branch being operable alternately with the high and low burners inthe other branch.

.low burner in one of its branches and including 8. In anunderfiredregenerative coke oven battery comprising a masonry massincluding coking" chambers, heating walls, regenerators, and regeneratordivision walls, all extending transversely of the battery. and havingvertical ilues one branch of each twin iiue of one heating wall, duringperiods alternating with the periods in which combustion is beinginitiated in a second set of vertical ues including the second branch ofeach of the twin ues of said heating wall, each heating wail having onesetoi' burners for one of its two sets of vertical ues and a second setof burners for its second set of vertical ues, the said. burners of oneset including some high l@ burners and some low burners, gas supplypassages for the low burners of each heating wail extending upwardlythrough one regenerator division wall adjacent said heating wall, andgas supply passages for'the high burners in the same heating wallextending upwardly through a regenerator division Walladjacent saidheating wall but at one side of the division wall including the supplypassages for the low burners of the same heating wall.

CARL OTTO.

